Dr. Howard (whose research records are part of the Archives’ collections) dedicated her career to breeding endangered species in captivity by adapting techniques commonly used for human infertility treatment. Much of her research focused on felines - clouded leopards, cheetahs, fishing cats, Florida panthers, and even domestic cats - and she frequently collaborated with zoos and wildlife conservation organizations throughout the United States, Africa, and Asia.

Howard also oversaw the black footed ferret breeding program at the National Zoo. In the 1980s, there were only 18 individuals left. Under her supervision, more than 500 kits were born, including more than 100 by artificial insemination. Many of these animals have been reintroduced into the wild. For her leadership in the effort, Howard was named "Recovery Champion" by the United States Fish and Wildlife Service in 2009.

The most famous result of her work was the birth of giant panda Tai Shan in 2005. Reproduction rates for giant pandas were low at zoos and breeding centers worldwide and the National Zoo had not produced a healthy panda cub after almost three decades of attempts. Howard worked with Chinese colleagues to develop new protocols for sperm cryopreservation and artificial insemination which contributed to a sharp increase in panda births. Howard was personally responsible for the artificial insemination of Mei Xiang, the National Zoo's female panda, that resulted in the birth of its first surviving cub.

Howard's success in the field of assisted reproduction earned her the nickname "Sperm Queen." In fact, her research records include thousands of images of both sperm and ova, as well as thousands of pages of sperm and ova data and data analysis. She was also a tireless and passionate champion for endangered species, who looked beyond biology to animal behavior and diet in order to understand the bigger picture. She also readily shared her knowledge, expertise, and skills with hundreds of fellows, interns, veterinarians, and wildlife specialists, and even the general public through interviews and television programs.

Howard died of cancer in 2011 at the age of 59, but left behind new clouded leopard facilities at the Smithsonian Conservation Biology Institute, reams of reproductive data, new protocols for breeding, a generation of veterinarians building upon her work, and healthier populations of several endangered species.